Early Life and Formative Years
Born in Andover, Massachusetts, Dan Koh comes from a family deeply rooted in public service and academia. His father, Dr. Howard Koh, served as the U.S. Assistant Secretary for Health under President Barack Obama, and his uncle, Harold Koh, is a former dean of Yale Law School who also served in the State Department. Koh's heritage is a mix of Korean and Lebanese immigrant backgrounds. He attended Phillips Academy in Andover before earning a bachelor's degree from Harvard College and an MBA from Harvard Business School, where he was president of his class section. This foundation of academic achievement and exposure to public life set the stage for a career that would blend management principles with government operations.
The Mayor's Right-Hand Man
At just 29, Koh was
appointed Chief of Staff to Boston Mayor Marty Walsh, a role that placed him at the center of the city's government. He was responsible for managing a workforce of 18,000 employees and a $3 billion budget. During his tenure, Koh became known for his focus on performance metrics and data. He was a key figure behind "CityScore," an award-winning system designed to track the city's performance on various services, from the quality of schools to the timeliness of street repairs. This period was marked by significant job growth and development in Boston, and Koh was recognized by Forbes' "30 Under 30" and the Boston Business Journal's "40 Under 40" for his impact.
A Razor-Thin Congressional Race
In 2018, Koh left his City Hall post to run for Congress in Massachusetts's 3rd congressional district. He entered a crowded Democratic primary, launching a vigorous grassroots campaign with thousands of volunteers. The race became one of the closest in the nation. After the initial vote count in the 10-way primary, Koh trailed his opponent, Lori Trahan, by just 122 votes. A district-wide recount confirmed Trahan's victory by a slightly larger margin of 145 votes out of nearly 90,000 cast. Though a defeat, the near-win demonstrated his significant fundraising ability and appeal to voters, establishing him as a serious political contender.
From the Private Sector to the White House
Following the 2018 election, Koh transitioned to the private sector, serving as the Chief Operating Officer of HqO, a technology company. However, his time in the corporate world was brief. He returned to his roots in public service by winning a seat on the Andover Select Board in 2019. When his former boss, Marty Walsh, was appointed U.S. Secretary of Labor in the Biden administration, Walsh tapped Koh to be his Chief of Staff. Koh's role in Washington expanded, and he eventually served in the White House as a Deputy Assistant to the President and deputy director of the Office of Intergovernmental Affairs, working on the implementation of major federal legislation.
A Second Run for Congress
In 2025, after incumbent Rep. Seth Moulton announced a run for the U.S. Senate, the seat for Massachusetts's 6th congressional district opened up. Koh launched his second bid for Congress, entering another competitive Democratic primary. This time, he emerged as the clear winner, securing the nomination on September 1, 2026, with a decisive margin over his closest rival. He now heads into the November general election. If successful, he would become Massachusetts's first Asian-American representative in Congress, marking another significant milestone in his career.
